Refueling systems are known in the art, by which fuel is transferred from a fuel source into a fuel consuming device, such as a vehicle. In an example of such system, a refueling vehicle provides a source of fuel for refueling a second vehicle. Refueling vehicles, for example, are commonly used for refueling aircraft. In such systems, fuel is transferred through conduits or pipe sections at a desired flow rate. In conventional refueling systems, a corrected differential pressure device may be inserted into flow paths of the system. A conventional corrected differential pressure device operates by measuring a pressure differential across a vessel in the refueling system. The pressure determinations are used to adjust the flow rate such that should the flow rate drop below the rated vessel flow rate, the pressure may be adjusted so as to achieve the desired flow rate
The sensors associated with a conventional correct differential pressure device control adjust the requisite pressure utilizing a flow rate input or determination. The flow rate often is measured using a flow meter. Conventional flow meters employ a rotating member, such as a rotatable fan or similar device, that is inserted longitudinally into a pipe section of the refueling system. The flow rate is measured based on the rate of rotation of the fan caused by the liquid fuel flowing through the pipe section. Because of the requisite size of conventional flow meters, pipe sections often must be specially cut or provided with undesirably large or specially designed fittings. Conventional flow meters, therefore, have proven to be difficult to employ.
As is known in the art, National Pipe Thread Taper (NPT) standards provide standards for tapered threads commonly used on threaded pipes and fittings. In refueling systems, for example, ¼ inch NPT fittings commonly are provided in one or more pipe sections of the system to provide internal access into the pipe section. NPT ¼″ pipe fittings may be employed to insert small probes, sensors, and similar monitoring devices into pipe sections for various maintenance and repair purposes. Because of the commonness of NPT ¼″ pipe fittings, it would be desirable to utilize such fittings for employing flow meters for use with corrected differential pressure devices. However, sizes and configurations of conventional flow meters are too large or otherwise wrongly shaped to employ conventional flow meters in NPT ¼″ pipe fittings. As referenced above, therefore, pipe sections often must be specially cut or provided with undesirably large or specially designed fittings for insertion of conventional flow meters.